The actor shared the photos to his Instagram account.
Jack shared some pictures from his life before the soap, showing throwbacks to his toddler and school years.
He also shared highlights of David, which included his bunny Barney, sharing a kiss with Tracy Barlow and a scene with girlfriend/stepsister Tina McIntyre.
Jack also included David's tougher moments which included being kidnapped by Richard Hillman, saying goodbye to wife Kylie, who was murdered and the shower scene when David realised he had been raped by Josh Tucker.
Jack captioned the post: "Today marks my 20th year anniversary playing the role of David Platt. Here's a few photos of my life before I got the part and a few highlights of my character. Thank you @coronationstreet for everything."
His friends and co-stars rushed to congratulate Jack on his achievement.
Our Girl star Michelle Keegan, who played Tina in Corrie from 2008 until 2014, commented: "Congratulations Jacky boy! Bloody amazing achievement, I hope that Tina tattoo is still imprinted on your arm. Here's to the next 20 years xxx."
Ryan Thomas, who played David's brother-in-law Jason Grimshaw joked: "No one mention!"
Kate Ford, who plays Tracy Barlow, aka Tracy McDonald, wrote: "Ha! X. Happy anniversary Jack."
Coronation Street fans have seen Jack grow up on screen and seen David deal with a lot of heartache.
What is David's current storyline?
David's current storyline has seen him having to deal with his wife Shona forgetting who he is.
Shona was shot on Christmas Day and eventually went into a coma. When she woke up, she had no memory of her life with David and his children Max and Lily.
All she seemed to remember is her own son Clayton, who killed David's first wife Kylie and took Shona hostage last year.
Unable to remember all the bad things he's done, or the fact she disowned him, Shona started contacting him again.
It was also revealed she wants to divorce David, leaving him heartbroken.
Will she ever remember who he is?
What are some of your favourite David Platt moments? Leave us a comment on our Facebook page @EntertainmentDailyFix and let us know what you think!